Safety cutoff control system with



May 20, 1952 2,597,787

SAFETY CUTOFF CONTROL SYSTEM WITH DUAL. THERMAL ELEMENTS c. M. GARNEREI'AL Filed May 26, 1947 IN 5 5 A/ To Es a RUDE M. GARNER, W14 L #701J'- HLLA/V, M 5% IIIIIIII'IIIIIIII v v-IIUIIIIII Patented May 20, 1952SAFETY CUTOFF CONTROL SYSTEM" WITH DUAL THERMAL ELEMENTS Claude M.Garner, Clayton, and-WilliamJ. Allan, Richmond Heights, :Mo.,assignorsto M-issouriw Automaticv Control Corporation, St; Louis, Moi;

a corporation of Missouri Application-May 26,1190, Serial No. 750,536

2 Claims (Cl. 158 127)' This invention relates to safety cut-off devicesfor use with fluid fuel burners, and more particu-.- larly to the tripand manual reset type in which a valve member being normally biasedtoward a fuel cut-off position may bemoved manually: 5

to an open and set position from which it is released or trippedautomatically upon loss of flame. at the burner.

Reference is made to the co-pendingapplica tion'of Claude M. Garner,Serial-Number 723,487, filed January 22, 1947, now abandoned, titledTemperature Responsive Device, upon-which the .present invention is animprovement.

Itis an object of the presentinvention to'pro'- valveis a valveactuating dicated at H; Fuel enters thevalve-IU througha conduit' 12 andis distributed to a main burner (shown in part)-generally indicated at13 and.-

to a pilot burner generally indicated at M through a fuel conduit [5 anda branch I6. Interposed in the fuel conduit 15 is a main burner control1y" operated: and controlled inaccordance with the requirementsofthespace to be heated. At-

tached to'the'pilot burner are apair of fluid filled bulbs I8 and I9;

Thecut-off valve H1 comprises" a valve bodyvide an improved safety fuel.cut-off mechanism, 15 -having-an inlet 2|, an outlet '22; :anda valvefor use with fluid fuelburners, which is actuated seat 23. Valve seat 23is tapered withits sides by a change in the pressure differential in apair converging towardthe outlet; There-is a'threadoffluidfilled-elements arranged to absorb'heat ed bore 24 in the bottomwall of valve body 10' at different rates from the burner, and in whichconcentric with valve seat 23, and adapted to one: of the elementshasgreater fluid capacity 20 receive a screw p1ug'25. There is also asmaller than-theother in order to maintain a minimum" bore 28 in theupper wall of the'valve body condifferential in workinglvolume when theelementscentric with. the seat 23 and adapted to receive aresubjectedtohigh ambient temperatures in .slidingfit relationship ,a valve stem 27.whichtend-to equalize-their temperatures and. Valve stem 'Z'I-is reducedat its lower end as therefore" thepressures of the fluids therein; 2indicated at 28and terminates in a rounded point Itis a further objectof thepresent invention to 29. The reduced portion 28 has a free fitrelaprovide-,== ina deviceof the above character, a tionship with theinner diameter of a short socket novel-poppettype valve and valvehousing strucmember '30. Socket member 3B,being a short turein-:whichthe valve is opened in a direction piece of tubing closed atits'lower end; is riveted opposedto the fiow andiin which access to the'30 toa cupesha'ped valve member 3|; interior of the valve housing foractuation of the Valve 3| has tap'eredisides and is arranged'for valvebyexternal means is at a point posterior of gas tight engagementwith' theseat 23. It will be thevalveand seat. 7 seen that valve 3| opens in adirection opposed Itis a further object of the present invention to.thezflow and that consequently line pressure to provide; inadeviceofthe above character, 35.assistsin holding; the valve'closedJ Aspring 32 novel means for manually opening and latching resting inarecess. 33 in screw plug normally in=an'-: open position a cut-offvalve,. wherein urges valve 3!. to a closed position; It will bestraight line valve actuating motion is achieved; seen that. with theprovision of the socket meme Further objects and advantages will appearber the free fit ofthelowerend 28 of valve from the followingdescription and accompany stem' 21' therein; and itsiroun-ded end, thevalve ing'drawings. Referring to the drawings: 3| may seeka perfectengagement with its seat Fig-"1 isza schematic illustration of a form ofunder the pressure of spring 32' without any the present invention, theview includes an *endanger of bias due to'any slight non-concentricitylarged 'cross sectional"view of the fuel cut-off f as'between the bore26 and seat 23'or as between valve-.and the valve actuating-mechanism;the stem 2T'and the valve 3| which may occur FigL Z is a cross sectiontaken on line 2-2-of in manufacture. Fig. 1; a v A frame 34 'whichencloses and supports the Figi 3 is a side view'of the pivoted detentshown valveactuating mechanism is mounted on valve in cross sectioninFig. 1 j body 20 and attached thereto'by screws'35. I Piv- Figw4 is anenlarged detail showing the knife otally supported on the left side offrame 34 on. edge'pivoting of the'detent. a pivot 36', is a horizontallyarranged U-shaped Fig. 5 is a plan view of the actuating lever; yoke 31,which carries pivoted near its open free Referring more particularly tothe drawings, 1 ends on a pivoted rod 38," 'an actuating lever 39. theschematic -view, Fig.- 1,. shows a fuel cut-off Lever 39 isalso-U-shapedhaving vertical legs-40 valve generally,indicated-atl0. Mounted onth'e.55 and-a horizontal-"connecting platform lI. In the assembly generally.in- I platform 41 are two conical shaped indentations 42, one on eachside of the pivoted connection 38.

There is a pair of vertically mounted, elongated expansible elements 43and 44 rigidly attached at their upper ends to the top cross member offrame 34 by studs 45 and nuts 46. These elements are of hollow, thintube construction having transverse corrugations, and their use andoperation are well known and understood in the art. These elements areprovided with solid fillers 41 and 43 which are soldered or brazed tothe inner walls of the elements at their outer ends to provide a jointwhich is gas tight under high pressure. These fillers serve the purposeof reducing the required volume of fluid in the system and minimizingthe portion of fluid in the system affected by ambient temperature andnot by the burner.

Studs 45 are formed as a part of upper fillers 41. There are horizontalbores 49 in upper fillers 4'! which receive capillary tubes 53 and andconnecting vertical bores 52 communicating with the interior of theelement. Lower fillers 43 have threaded bores 53 which receive adjustingstuds 54. Lock washers 55 and lock nuts 56 are provided for lockingstuds 54 in an adjusted position.

Studs 54 have conically pointed lower ends which center in the conicalindentations 42 in the horizontal platform portion of actuating lever39. Lever 39 is held constantly in contact with the lower ends of studs54 by return springs 57. Springs 51 are held in position at their lowerends by fitting over the heads of screws 35 and at their upper ends byfitting over the convex cones which incidentally result when forming theconical indentations 42.

Slidably mounted in a bushing 58 secured to the top cross member offrame 34 is a vertical manual reset plunger 59. Plunger 59 has a disc 65riveted to its upper end and there is a return spring 61 which normallyholds plunger 59 in its uppermost position. A collar 62 on plunger 59limits its upward travel. The lower end of plunger 59 has a conicalpoint arranged to engage with a conical recess 63 in the upper end ofthe valve stem 21.

Valve steml'l has a reduced portion 54 at its upper end providing asharp square shoulder 65. Adjacent and parallel with plunger 59 andvalve stem 27 is a vertical plate-like detent 55. The detent 66 haslateral projections 51 at its upper edge '(see Fig. 3) which engagetriangular slots 68 in the horizontal plate members 69 which areattached to the upper part of frame 34. Thereby knife edge pivoting ofdetent 85 about its upper edge is provided. The lower edge of detent 55is arranged to abut the shoulder 65 of the valve stem under certainconditions thus holding valve 3! open against the pressure of spring 32.The lower edge of detent 65 is normally urged toward the valve stem by aspring 15.

The upper ends of vertical legs 40 of actuating lever 39 are formed at aright angle providing the short horizontal portions H which, as lever 39is rotated counterclockwise on its pivot 38, engage the detent 6E. Thehorizontal portion 4! of the actuating lever 39 has a rectangularperforation 12 through which pass the detent, the plunger and the valvestem.

l The fluid filled elements it and i9 are supported on the base of thepilot burner M by a clamp type support member [3. Elements i8 and 19 areconnected to the expansible elements 43 and 44 respectively by fluidconduits 5G and 5| as indicated. The disposition of elements !8 and ISwith relation to the pilot burner head 14 and the flame issuingtherefrom, is such that element [8 will receive heat at a greater ratethan element [9. Also element 19 has less fluid capacity than element l8whereby although the ambient temperature within the burner enclosure maycause the temperature, and therefore the pressure, of the fluid in 19 toclosely approach that in element l8, even with the pilot flame burning,there will be a sufficiently greater volume available in bulb l8 toinsure the relatively greater expansion of expansible element 43 and toprevent the device from functioning to cut oil the fuel supply.

It is apparent that by adjusting springs 51 so as to preload expansible'element 44 to a greater extent than element 43, a minimum differentialin expansion of elements 43 and 44 could be maintained even though bulbsI8 and is were of the same capacity. The expansion diiferential couldthus be maintained constant throughout a temperature range in which bothfluid filled elements were of the same temperature. The use of bulbs ofdifferent capacity has, however, proven to be a more satisfactoryexpedient in practice, chiefly because of the great difference in springloading required to achieve the same effect, which difference wouldeither require a spring loading so light on one hand as to be impositivein action and for a loading so heavy on the other hand as to set upundue stresses in the movable parts. Valve stem 2'! has a flange l5intermediate of its lengthwhich together with a resilient sealing Washer76 provides a seal against leakage of fuel through the bore 25 when thevalve 3! is open.

I n operation In the drawing, Fig. 1, the mechanism is shown in theburner-on operating position. Fluid filled elements [8 and [3 are bothreceiving heat from the pilot burner. Element l8 however is receivingheat at a greater rate than element l9 and as a result there is agreater fluid pressure in expansible element 43 than in element 44. Thisin turn has resulted in the greater relative expansion of element 43 andtherefore the clockwise rotation of actuating lever 39. This clockwiserotation of lever 39 has caused its portions H to be moved sufficientlyin a direction away from detent 66 topermit its lower edge to swing intoposition under the urging of spring 10, and to abut the shoulder of thevalve stem Z'L thus latching valve 3| in an open position. Valve 3! willhave been previously opened man- 3:113 by pushing downwardly on resetplunger After ignition of the pilot burner, elements l8 and I9 continueto absorb heat and expansible elements 43 and 44 will continue to expanduntil heat absorption and heat loss stabilize. A differential in heatabsorption by bulbs 18 and I9 and therefore a differential in expansionof the expansible elements will however maintain throughout the range.This differential may be achieved and/or varied by the relativedisposition of bulbs l8 and IS with respect to the burner flame or byshrouding, baffling, etc.

By maintaining the differential at a practical minimum it will be seenthat upon loss of flame, this differential, or a substantial part of it,will be quickly lost, irrespective of the temperature level. This lossof differential will result in a relative contraction of element 43, andunder the urging of a spring 51, actuating lever 39 will be rotatedcounterclockwise and by engagement of its portions H with detent 66 willpush the detent from the valve stem shoulder 85 thus tripping themechanism and permitting valve 3| to close.

When it is desired to relight the pilot burner, the plunger 69 is pusheddownward, thereby pushing valve stem 21 downward and opening valve 3|.By pushing valve stem 21 downward until resilient Washer 16 abuts theseat at the upper end of the bore 26, a seal against fuel loss 1 isprovided. It is obviously also necessary to push valve stem.27 downwardsufiiciently to permit the lower edge of detent 66 to swing in andengage the shoulder 65. The resiliency of washer '56 will permitcompensation for slight manufacturing variations and insure both a sealfor bore 26 and clearance for engagement of the detent with shoulder 65.

After the fuel valve 3| is manually opened the plunger 69 is held downwhile the pilot burner is ignited, and thereafter until bulb I8 hasabsorbed sufiicient heat from the burner flame to cause the necessaryexpansion of element 53, and the necessary clockwise rotation of lever39 to permit the swinging into engagement of detent 66 with shoulder 65under the urging of spring 79. The line 31 valve is thus latched in anopen position.

By the arrangement of pivoting actuating lever 69 on the free end ofpivoted yoke 31, both rotational and substantially verticalmovement oflever 39 is provided, to take care of both relative and similarexpansion or contraction of elements 43 and 44.

The foregoing description is intended to be illustrative and notlimiting and the exclusive use of all modifications within the scope ofthe appended claims is contemplated.

We claim:

1. In a temperature responsive fuel cut-01f device in combination, aburner, a valve, resilient means for holding said valve in a closedposition, means for opening said valve, means for releasably holdingsaid valve in an open position, valve releasing means including a levermovable toward and away from a valve releasing position, conditionresponsive means for actuating said lever comprising a first fluidfilled element disposed adjacent said burner so as to receive heattherefrom, a first expansible element, fluid conduit means connectingsaid first elements, said first expansible element being operativelyconnected to one part of said lever, a second fluid filled element alsodisposed adjacent said burner but arranged to absorb heat therefrom at aslower rate than said first fluid filled element, a second expansibleelement having the same proportions as said first expansible element,and fluid conduit means for connecting said second elements, said secondfluid filled element having less fluid capacity than said first fluidfilled element, whereby a greater expansion of said first expansibleelement is maintained at high ambient temperatures, said secondexpansible element being operatively connected to another part of saidlever, the arrangement being such that expansion of said firstexpansible element with relation to said second expansible elementcauses the lever to move away from a valve releasing position andexpansion of said second expansible element with relation to said firstexpansible element causes the lever to move toward a valve releasingposition.

2. In a temperature responsive fuel cut-off device in combination, aburner, a fuel supply system for said burner, a valve in said system, afirst fluid filled element disposed adjacent said burner so as toreceive heat therefrom, spring means for holding said valve in a closedposition, means for releasably holding said valve in an open position,valve releasing means including a lever movable to a valve releasingposition, means for opening said valve, a first expansible element,fluid conduit means connecting said first elements, said firstexpansible element being operatively connected to one part of saidlever, a second fluid filled element also disposed adjacent said burnerbut arranged toabsorb heat therefrom at a slower rate than said firstfluid filled element, a second expansible element having the sameproportions as said first expansible element and fluid conduit means forconnecting said second elements, said second fluid filled element havingless fluid capacity than said first fluid filled element, whereby adifferential in expansion of said expansible elements will be maintainedeven though both fluid filled bulbs attain the same temperature, saidsecond expansible element being operatively connected to another part ofsaid lever, the arrangement being such that relative expansion of saidfirst expansible element causes the lever to move away from a valvereleasing position and a relative contraction of said first expansibleelement causes the lever to move toward a valve releasing position.

CLAUDE M. GARNER. WILLIAM J. ALLAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,325,896 Long Dec. 23, 19191,563,532 Shadrick Dec. 1, 1925 1,773,817 Leach Aug. 26, 1930 1,823,122Partlow Sept. 15, 1931 1,828,424 Lovekin Oct. 20, 1931 1,846,814 RuudFeb. 23, 1932 1,848,668 Scott Mar. 8, 1932 1,850,646 Ross-Watt Mar. 22,1932 1,977,150 Schmidt Oct. 16, 1934 1,994,983 DeFlorez, et al Mar. 19,1935 2,171,815 Thomas Sept. 5, 1939 2,295,455 Dillman Sept. 8, 19422,379,124 Wasson June 26, 1945

